Design and optimization of an airflow-vibration sieving device for the effective cleaning of cyperus esculentus L.harvesting mixture

The threshing mixture of Cyperus esculentus(Tiger nut)planted in sandy areas is complex during harvesting,and there are problems of high impurity rate and high cleaning loss rate of the seeds.In this paper,the threshing mixture of Cyperus esculentus is taken as the research object,and the suspension speed of each component is measured to design an“airflow+vibration”sieving device.Use the vector polygon method to explore the law of motion of the vibrating sieve,establish the force model of the seeds on the sieve surface,and analyze the conditions for the seeds to penetrate the sieve.According to the principle of seeds penetrating the sieve and long stalks not penetrating the sieve,the geometric model of sieve blades opening degree adjustment mechanism is constructed.Study of the conditions under which long stalks can be thrown out of the machine.The experiment bench of the cleaning device was built,and the evaluation indexes were the rate of seed impurity and the rate of cleaning loss of the device,and the crank speed,sieve blades opening degree and fan speed were used as the experiment factors to study the influence law of each influencing factor on the evaluation index through single-factor experiment.Using response surface methodology to find the optimal combination of working parameters of the cleaning device.To verify the device’s application on the combine harvester to improve the effectiveness of the cleaning operation of the Cyperus esculentus combine harvester.

器械清洗预处理与清洗消毒合格率的关系研究

目的探讨复用医疗器械清洗前预处理对清洗效果的影响。方法选取2019年12月我院消毒供应室回收的1600件止血钳,根据使用时间先后随机分为对照组和实验组,每组800件。对照组按照常规流程清洗,实验组使用含酶保湿剂预处理后清洗,比较两种方法的清洗效果。结果使用含酶保湿剂预处理后器械清洗效果显著提高,实验组器械表面蛋白残留阳性率(3.8%)显著低于对照组(11.3%),差异有统计学意义(p<0.05);实验组器械表面隐血合格率显著高于对照组,差异有统计学意义(p<0.05);但器械表面细菌菌落数无明显改变(p>0.05)。在此基础上,进一步对两组器械进行常规消毒灭菌后,发现使用含酶保湿剂预处理的实验组蛋白残留阳性率率(0.3%)低于对照组(1.8%),实验组器械表面隐血合格率(98.9%)显著高于对照组(93.6%),但两组均未见细菌残留。结论对复用医疗器械进行合理的预处理能够有效提高器械清洗合格率,预处理需要长效保湿及酶剂的协同作用,方能有效提高预处理效率。含酶保湿剂不具备杀菌作用,需要进一步加强复用器械清洗后的消毒、灭菌措施,以提高细菌菌落合格率,保证器械消毒灭菌效果。

Design and parameters optimization of the curved sieve for an air suction jujube harvester

In order to improve the screening performance and cleaning effect of the jujube harvesting machinery cleaning device,a vibrating curved screen device was designed in this study.By analyzing the structure mechanism of the curved sieve body,it was obtained that the arc-shaped mesh hole spacing S was 15-25 mm and the curved mesh hole curvature U was 90°-150°.By exploring the movement state and stress of jujube and impurities on the curved sieve body,it was determined that the horizontal spacing L of the curved layer sieve was 30 mm and the vertical spacing H was 45-65 mm.Taking the vertical spacing H of the curved layer sieve,the curvature U of the curved mesh hole,and the spacing S of the curved mesh hole as the experimental factors,considering the screening efficiencyαand the impurity contentβof the jujube as the response values,the three-factor three-level quadratic regression orthogonal experiment was designed,establishing the regression mathematical model of each factor and response value,and the multiple target optimization algorithm of Design-expert software was used to optimize various factors.The results showed that the influence factors on the screening efficiency were in the descending order as:the arc screen spacing,the vertical spacing of the curved layer screen,and the curved screen hole curvature;The significant factors affecting the impurity content of jujube were in the descending order as:the arc screen spacing,the curved screen hole curvature,and the vertical spacing of the curved layer screen.The experimental results were verified by the optimized combination of parameters:when the vertical spacing H of the curved layer screen was 65 mm,the curved screen hole curvature U was 110°,and the arc screen spacing S was 23 mm,the average screening efficiencyαin the test was 91.09%.The relative error between the experimental verification value and the theoretical optimization value was 1.36%,which was less than 5%.The impurity content of jujubeβin the test was 1.02%.The relative error between the experimental verification value and the theoretical optimization value was 2.00%,which was also less than 5%.The test results can provide a reference for the research and optimization of the subsequent air-suction-type jujube harvester cleaning device.

Simulation and test on separating cleaning process of flax threshing material based on gas-solid coupling theory

In order to further clarify and improve the working performance of separating cleaning device of flax threshing material,and study the motion law and characteristics of components of flax threshing material,in this paper,numerical simulation was carried out on the separating cleaning process of flax threshing material based on CFD-DEM method.Simulation results showed that the components of flax threshing material were separated and cleaned under the influence of airflow field,meanwhile,variation curves of quantity and mean velocity of flax seeds in the separating cleaning system were obtained.By referring to streamline distribution of gas-solid coupling,the quantity variation law of components of flax threshing material with time was explored and their motion curves and variation tendency of average velocity were studied.Verification test results showed that the cleaning rate of separating cleaning device for flax threshing material was 92.66%with 1.58%of total separation loss.Compared with simulation results,the test results were 1.34%and 0.93%lower,showing that it is feasible to apply the gas-solid coupling theory and method to simulate the separating and cleaning operation of flax threshing material.

Eyelid margin cleaning using Deep Cleaning Device for the treatment of meibomian gland dysfunction-associated dry eye: a preliminary investigation

Objective: To evaluate the safety and effectiveness of eyelid margin cleaning using Deep Cleaning Device for the treatment of meibomian gland dysfunction-associated dry eye. Methods: This was a prospective, randomized, open-label, investigator-masked, and self-controlled study. We randomly assigned one eye of patients with meibomian gland dysfunction-associated dry eye to the treatment group, and the other eye to the control group. Both groups received artificial tears and lid warming;the treatment group received an additional one-time in-office eyelid margin cleaning using Deep Cleaning Device. Non-invasive tear break-up time(NITBUT) and tear meniscus height(TMH) of each eye, and Standard Patient Evaluation for Eye Dryness II(SPEED II) score of each patient were evaluated before and at one week after treatment. Results: Thirty eyes of 15 patients were enrolled. No adverse effects occurred during the treatment. Compared with the baseline values, the SPEED score decreased significantly at one week after treatment(mean±95% confidence interval, 11.00±0.99 vs. 5.67±1.67, P<0.0001), the NITBUT-first in the treatment group increased significantly at one week after treatment((4.74±1.27) s vs.(7.49±2.22) s, P=0.01). The NITBUT-first was significantly longer in the treatment group((7.49±2.22) s) than in the control group((5.17±0.91) s) at one week after treatment(P=0.042). No significant differences were found in other tear film parameters between the two groups. Conclusions: Eyelid margin cleaning using the novel Deep Cleaning Device is a convenient, effective, and safe treatment for patients with meibomian gland dysfunction-associated dry eye.